This invention relates to a ground working implement of the type including a tool bar which is mounted for movement across ground to be worked, a ground working tool for engagement with the ground and an attachment bracket for mounting the tool on the tool bar so that a forward pulling force is applied to the tool by the tool bar.
The invention is particularly but not exclusively concerned with an attachment bracket for ground working tools such as packers or active harrow elements which are mounted for rotation about an axis transverse to the forward movement of the bar and have a width substantially greater than the distance of the axis from the tool bar.
In the seventies and early eighties, ground working tools of this type such as packers have been trailed well behind a tool bar on a long tongue. In more recent years however, this previous design has been found to be relatively cumbersome both from the point of view of changing to a transportation mode and from the point of view of the relatively large overlap which is necessary between adjacent tools to ensure proper action on all parts of the ground without spaces between the tools. A modified arrangement for packers and similar devices has therefore been recently adopted by many manufacturers in which the rotation shaft of the packer is supported on a pair of arms each directly connected to the tool bar by a suitable bracket with the arm having a substantially minimum length to allow the packer to trail behind the tool bar and extend from the tool bar downwardly to the ground. This device has achieved substantial success but there remain difficulties in providing the twisting action which is necessary should one end of the tool be lifted by the ground relative to the other end.
In addition problems arise where it is required to mount a tool of this type, for example a harrow element or a packer element rearwardly of an existing tool bar for example of a cultivator which already carries a number of cultivator shanks. This problem arises in that the conventional method for attachment of the brackets for the arms of the tools is by U-shaped clamps which engage around the tool bar and support the bracket and the arm on a rear face of the tool bar. The necessity for a pair of such clamps for each tool element often causes problems of obtaining enough space on the tool bar to accomodate all of the necessary clamping elements and other equipment carried by or mounted on the tool bar. This interferes with the proper and orderly location of the tool elements on the tool bar.